Plant nutrient uptake and productivity are driven by a multitude of factors that have been modified by human activities, like climate change and the activity of decomposers. However, interactive effects of climate change and key decomposer groups like earthworms have rarely been studied. In a field microcosm experiment, we investigated the effects of a mean future climate scenario with warming (+ 0.50 °C to + 0.62 °C) and altered precipitation (+ 10% in spring and autumn, − 20% in summer) and earthworms (anecic—two Lumbricus terrestris, endogeic—four Allolobophora chlorotica and both together within 10 cm diameter tubes) on plant biomass and stoichiometry in two land-use types (intensively used meadow and conventional farming). We found little evidence for earthworm effects on aboveground biomass. However, future climate increased above- (+40.9%) and belowground biomass (+44.7%) of grass communities, which was mainly driven by production of the dominant Festulolium species during non-summer drought periods, but decreased the aboveground biomass (− 36.9%) of winter wheat. Projected climate change and earthworms interactively affected the N content and C:N ratio of grasses. Earthworms enhanced the N content (+1.2%) thereby decreasing the C:N ratio (− 4.1%) in grasses, but only under ambient climate conditions. The future climate treatment generally decreased the N content of grasses (aboveground: − 1.1%, belowground: − 0.15%) and winter wheat (− 0.14%), resulting in an increase in C:N ratio of grasses (aboveground: + 4.2%, belowground: +6.3%) and wheat (+5.9%). Our results suggest that climate change diminishes the positive effects of earthworms on plant nutrient uptakes due to soil water deficit, especially during summer drought.

植物养分吸收和生产力是由人类活动改变的多种因素驱动的，例如气候变化和分解者的活动。然而，气候变化与蚯蚓等关键分解群体的相互作用影响却很少被研究。在现场微观实验中，我们研究了未来平均气候情景对变暖（+ 0.50 °C 至 + 0.62 °C）和降水量变化（春季和秋季 + 10%，夏季 - 20%）和蚯蚓（两种土地利用类型（集约化利用的草地和传统农业）中植物生物量和化学计量的影响。我们几乎没有发现蚯蚓对地上生物量影响的证据。然而，未来气候增加了草群落的地上（+40.9%）和地下生物量（+44.7%），这主要是由非夏季干旱期间主要羊粪菌属物种的生产驱动的，但地上生物量减少了（− 36.9 %) 冬小麦。预计的气候变化和蚯蚓会交互影响草的氮含量和碳氮比。蚯蚓提高了氮含量（+1.2%），从而降低了草中的碳氮比（−4.1%），但仅限于周围气候条件下。未来的气候处理普遍降低了牧草（地上：− 1.1%，地下：− 0.15%）和冬小麦（− 0.14%）的氮含量，导致牧草的碳氮比增加（地上：+ 4.2%） ，地下：+6.3%）和小麦（+5.9%）。我们的研究结果表明，由于土壤缺水，特别是在夏季干旱期间，气候变化削弱了蚯蚓对植物养分吸收的积极影响。